Method for preparing high-throughput composite forward osmosis membrane

A forward osmosis membrane, high-flux technology, applied in the direction of semi-permeable membrane separation, chemical instruments and methods, membrane technology, etc., can solve the problem of unfavorable water and solvent rapid exchange, the inability to form an open bottom surface structure, and low forward osmosis flux to achieve the effects of reducing internal concentration polarization, increasing water flux, and reducing structural parameters

Active Publication Date: 2016-12-14
OCEAN UNIV OF CHINA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, no matter in the laboratory or in industrial production, the dense and non-porous substrate (glass or stainless steel) is used as the film-forming substrate to prepare the base film. The non-porous and dense substrate is not conduci

Method used

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  • Method for preparing high-throughput composite forward osmosis membrane
  • Method for preparing high-throughput composite forward osmosis membrane
  • Method for preparing high-throughput composite forward osmosis membrane

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0046] Example 1: A stainless steel microporous membrane is used as the substrate.

[0047]Preparation method: replace the glass plate with a stainless steel microporous membrane, and the rest of the steps are the same as in Comparative Example 1. The high-performance composite forward osmosis membrane prepared is fully washed with deionized water and stored in 0.1% sodium bisulfite solution.

[0048] Performance: With 1M NaCl and deionized water as the draw liquid and raw material liquid, the forward osmosis water flux is 38.6±2.3LMH, the reverse salt flux is 8.0±1.9gMH, and the brine ratio is 0.21g / L.

[0049] Structure: The membrane is composed of a porous support layer and a dense separation layer. The bottom surface structure is completely open. The spongy layer in the support layer is extremely thin, and the finger-shaped holes almost run through the entire section of the membrane. The overall thickness of the membrane is about 100 μm. The structural parameter is 172.5 μ...

Embodiment 2

[0050] Example 2: Using a porous sieve plate as the base.

[0051] Preparation method: Replace the glass plate with a porous sieve plate, and the rest of the steps are the same as in Comparative Example 1. The high-performance composite forward osmosis membrane prepared is fully washed with deionized water and stored in 0.1% sodium bisulfite solution.

[0052] Performance: With 1M NaCl and deionized water as the draw liquid and raw material liquid, the forward osmosis water flux is 31.9±3.0LMH, the reverse salt flux is 6.1±1.3gMH, and the brine ratio is 0.20g / L.

[0053] Structure: The membrane is composed of a porous support layer and a dense separation layer. The bottom surface has a high porosity ratio. The spongy layer in the support layer is extremely thin. The finger-shaped holes almost run through the entire section of the membrane. The overall thickness of the membrane is about 100 μm. The structural parameter is 235.8 μm.

Embodiment 3

[0054] Embodiment 3: using a ceramic microporous membrane as a substrate.

[0055] Preparation method: Replace the glass plate with a ceramic microporous membrane, and the rest of the steps are the same as in Comparative Example 1. The high-performance composite forward osmosis membrane prepared is fully washed with deionized water and stored in 0.1% sodium bisulfite solution.

[0056] Performance: With 1M NaCl and deionized water as the draw liquid and raw material liquid, the forward osmosis water flux is 36.3±0.4LMH, the reverse salt flux is 8.5±1.4gMH, and the brine ratio is 0.24g / L.

[0057] Structure: The membrane is composed of a porous support layer and a dense separation layer. The bottom surface is a completely open structure. The support layer is composed of a very thin spongy layer and a finger-shaped pore layer with a small tortuosity. The overall thickness of the membrane is about 100 μm. The structural parameter is 190.7 μm.

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Abstract

The invention discloses a method for preparing a high-throughput composite forward osmosis membrane. The method comprises the following steps: (1) preparing a polysulfone solution, standing and defoaming at room temperature to obtain a uniform membrane casting solution; (2) fixing a filter screen on a membrane forming substrate made of a porous material, coating the polysulfone membrane casting solution to the filter screen, and soaking in a gel bath for phase transformation to obtain a porous supporting layer; (3) soaking the porous supporting layer respectively in MPD and TMC solutions for interface polymerization to generate an active separation layer; and (4) heating to prepare the polysulfone composite forward osmosis membrane. The method has the advantages that due to the porous structure of a membrane forming substrate made of the porous material, water entering the membrane has a higher speed than that of a traditional nonporous substrate in the phase transformation stage, exchange of water and solvent has a high speed, and a perforative finger-like pore structure and an opening bottom structure can be easily formed, so that the membrane structure parameter can be reduced, the concentration polarization in the forward osmosis process can be finally reduced greatly, and the water flux of a composite forward osmosis membrane can be greatly improved.

Description

technical field [0001] The invention relates to a preparation method of a separation membrane, in particular to a preparation method of a composite forward osmosis membrane. Background technique [0002] In recent years, with the huge demand for global energy and water resources, forward osmosis (FO) has received renewed attention as a potential alternative technology for seawater desalination, food processing, wastewater treatment, and energy development. Compared with the reverse osmosis (RO) process, the forward osmosis process not only has the advantage of saving energy without external pressure, but also because of the low pressure tightness between the membrane and the pollutant layer, the forward osmosis membrane is not easy to scale and easy to clean. However, commercial reverse osmosis membranes can achieve high water flux, while the current water flux of forward osmosis membranes is still low. Therefore, in order for forward osmosis technology to be widely used, i...

Claims

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Application Information

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IPC IPC(8): B01D69/12B01D67/00B01D61/00
CPCB01D61/002B01D67/0002B01D69/12
Inventor 王铎胡乐乐
Owner OCEAN UNIV OF CHINA
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